In the past I have, at times, been somewhat critical of the National School Lunch Program (NSLP) guidelines destined to make school lunches healthier by reducing calories, sodium content, saturated fat, etc. It's not not that I'm against healthy kids! Rather, I bristled at the idea of a bunch of nutritionists, policy makers, etc. setting rules and guidelines for how they think kids should eat without considering how the children would respond to the rules. Nutritional content is but one of the components we care about when eating - don't we also care about how the food tastes, how much it costs, whether it leaves feeling full, whether it is safe to eat, etc. etc. In short, the guidelines were established with limited understanding of what children want to eat, and as such we knew very little about whether the rules might increase food waste, increase the frequency of home lunches, cause unintended substitution patterns, and so on.
In an interesting paper in the most recent edition of the American Journal of Agricultural Economics, a team of six researchers sought to do what should have been done prior to implementing nutritional guidelines. In particular, the authors studied almost 280,000 school lunch choices of about 5,500 elementary age children in a suburban South Carolina school district. The authors know the precise foods available at each lunch offering, the nutritional characteristics of the foods, which foods the child selected (or whether the child brought a lunch from home - note that lunch menus were published well in advance), and some of the characteristics of the child who made the choice such as their grade, gender, race, and whether they received free or reduced price lunch.
The authors are able to take all this data to estimate demand curves associated with different food offerings. Their demand models let them answer questions like the following:
- If the sodium content of a pizza offering were lowered, how would that change the number of children who select it?
- If a low fat pizza is paired with a peanut butter sandwich, which would most people choose?
- If the caloric content were unilaterally lowered on all offerings, how many more children would bring their lunches from home?
Here's what the authors find: